1. Field
The present invention relates to a radio communication system, and more particularly, to a method for a transmitting end to generate and use a plurality of demodulation reference signals (DM-RSs) so as to report a structure of a precoder to a receiving end in a radio communication system that transmits and receives information through use of a multiple input multiple output (MIMO) antenna.
2. Discussion of the Background
As communication systems have developed, various wireless terminals have been utilized by consumers, such as companies and individuals.
A current mobile communication system, for example, 3GPP, Long Term Evolution (LTE), LTE-Advanced (LTE-A), and the like, may be a high capacity communication system capable of transmitting and receiving various data such as image data, wireless data, and the like, beyond providing a sound-based service. Accordingly, there is a desire for a technology that transmits high capacity data, which is comparable with a wired communication network. Also, the system is required to include an appropriate error detection scheme that increases transmission efficiency of the system so as to improve performance of the system.
In the communication system, a demodulation reference signal (DM-RS) may be used to report, to a receiving apparatus, information associated with a precoder used by a transmitting apparatus for information transmission.
Both a transmitting end and a receiving end of the communication system use a multiple input multiple output (MIMO) antenna, and a different DM-RS may need to be transmitted to each layer where a user equipment (UE) transmits or receives a signal.
In general, a layer refers to an independent information stream of simultaneously transmitted different pieces of information, and a rank refers to a number of layers or a maximum number of layers that can be simultaneously transmitted.
Although a process of mapping a DM-RS, different for each layer, to a transmission block or a resource block has been discussed, specifications have not yet been determined.
In particular, there is a drawback in that an effective multiple access environment may not be provided through use of merely a conventional cell-specific DM-RS sequence in a multi-user MIMO environment where UEs access a single base station.